My guess is that when you threaded the machine, you put the pressure foot down before you threaded it all the way to the needle. It looks to me like the thread didn't get between the tension disks properly.
My suggestion..rethread from the beginning and don't lower the pressure foot (to get at the needle) until you are ready to thread the needle. Also check that the bobbin is correctly inserted. However, this looks like what a friend had on the back of her sewing when the thread wasn't correctly between the tension disks.